Generally speaking, the present invention relates to smoke and heat detectors and more specifically to smoke and heat detector systems which produce an audible alarm utilizing a piezoeletric transducer. In the present invention a high output audible alarm means which includes a piezoelectric transducer and a voltage doubling means in combination with a smoke and heat detector which includes a low voltage power supply source, an ionization sensing chamber, and an ambient temperature detecting means; a logic driving means; and an acoustics enhancement means produce a high output smoke and heat detector alarm system.
Smoke and heat detectors which utilize ionization sensing chambers and an ambient temperature detecting means typically have two or more electronic circuits which are responsive to only one of the sensing or detecting devices. Such design techniques in previous smoke and heat detectors have resulted in discrete circuit elements which serve no more than one function. Accordingly, previous smoke and heat detectors which utilize such design techniques involve inefficient utilization of materials and power and therefore typically the cost of such detectors reflect this inefficiency.
Smoke and heat detector alarm systems have previously not utilized piezoelectric transducers because of the necessity to use a high voltage power supply source in order to produce an audible alarm signal of sufficient decibels to be useful as a warning system and, more recently, to meet government requirements for decibel levels of the audible output of smoke and heat detector alarm systems. Accordingly, where it has previously been desirable to utilize low voltage power supply sources in smoke and heat detector alarm systems an electromechanical horn or similar devices which are capable of producing a high decibel audible alarm using a low voltage supply source have been utilized. However, the use of devices such as electromechanical horns which are physically large, results in an audible alarm means which is segregated from the smoke and heat detector circuitry. The total smoke and heat detector alarm system therefore comprises the interconnection of descrete elements which results in the inefficient use of both power and material. Smoke and heat detector alarm systems utilizing electromechanical horns and similar devices along with associated circuitry to drive such devices also require large stand-by currents and large operating currents. The demand for large currents from low voltage power supply sources makes it necessary to use specially designed power supply sources which may not be readily available to the consumer.
Accordingly, it is a feature of the present invention to provide a totally integrated smoke and heat detector. Another feature of the present invention is to provide a highly efficient and low cost smoke and heat detector which includes a low voltage power supply source, an ionization sensing chamber, an ambient temperature detecting means, a voltage amplitude comparing means, and a low voltage sensing means. Another feature of the present invention is to provide a high output smoke and heat detector alarm which is a totally integrated system. Another feature of the present invention is to provide a smoke and heat detector alarm system utilizing a piezoelectric transducer and a voltage doubling means which produce a high output audible alarm. Another feature of the present invention is to provide a high output smoke and heat detector alarm system utilizing a piezoelectric transducer and a voltage doubling means which is responsive to a low voltage supply source of the type readily available to the average consumer. Another feature of the present invention is to provide a high output smoke and heat detector alarm system which includes integrated logic circuitry. Yet another feature of the present invention is to provide a totally integrated high output smoke and heat detector alarm system comprising a highly efficient smoke and heat detector which includes a low voltage power supply source, at least one ionization sensing chamber, and an ambient temperature detecting means; a logic driving means; a high output audible alarm means which includes a piezoelectric transducer and a voltage doubling means; and an acoustics enhancement means.
These and other features of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings which follow: